package com.tanhua.admin.utils;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

/**
 * @ClassName CodeUtils
 * @Description TODO
 * @Author JavaDev
 * @Date 2021/1/16 19:06
 * @Version 1.0
 */
public class CodeUtils {
    public static String getCode(HttpServletRequest request, HttpServletResponse response) throws IOException {



        // 使用java图形界面技术绘制一张图片

        // 验证码个数
        int charNum = 4;
        // 图片宽度
        int width = 20 * 5;
        // 图片高度
        int height = 30;

        // 1. 创建一张内存图片
        BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

        // 2.获得绘图对象(画笔)
        Graphics graphics = bufferedImage.getGraphics();

        // 3、绘制背景颜色
        graphics.setColor(getRandColor(200, 250));
        graphics.fillRect(0, 0, width, height);

        // 4、绘制图片边框
        graphics.setColor(Color.GRAY);
        graphics.drawRect(0, 0, width - 1, height - 1);

        // 5、输出验证码内容
        graphics.setColor(Color.RED);
        graphics.setFont(new Font("宋体", Font.BOLD, 22));

        // 随机输出4个字符
        String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890";
        Random random = new Random();

        // session中要用到
        String code = "";

        int x = 5;
        for (int i = 0; i < charNum; i++) {
            int index = random.nextInt(str.length() - 1);
            String content = String.valueOf(str.charAt(index));

            code += content;
            graphics.setColor(new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255)));
            graphics.drawString(content, x, 22);
            x += 20;
        }

        //将验证码放入HttpSession中
        request.getSession().setAttribute("VER_CODE_SERVER", code);
        System.out.println("设置的验证码为:" + request.getSession().getAttribute("VER_CODE_SERVER"));

        // 6、绘制干扰线
        graphics.setColor(Color.GRAY);
        for (int i = 0; i < 5; i++) {
            int x1 = random.nextInt(width);
            int x2 = random.nextInt(width);

            int y1 = random.nextInt(height);
            int y2 = random.nextInt(height);
            graphics.drawLine(x1, y1, x2, y2);
        }

        // 释放资源
        graphics.dispose();

        // 图片输出 ImageIO
        ImageIO.write(bufferedImage, "jpg", response.getOutputStream());
        return code;
    }


    /**
     * 得到随机颜色
     */
    private static Color getRandColor(int fc, int bc) {// 给定范围获得随机颜色
        Random random = new Random();
        if (fc > 255) {
            fc = 255;
        }
        if (bc > 255) {
            bc = 255;
        }
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }
}
